6 week old small lab
my chocolate lab is 6 and half week her sister who is with my sister in law is twice as big,she eats 3 maybe 4 small meals a day, sleeps and plays, is very clever she knows her name and wees and poos on puppy pad next to the door, she doesn't play as much as her sister tho i put this down to the fact her sister is bigger with more energy.
she has grown 2cms in the last week and was the biggest born but she is very laid back and i suspect she let the others feed first!! she is at the vets next thursday! do you think she will catch up??
There can be a big difference in size between puppies of the same breed, even in the same litter... and size at birth often doesn't have much influence on size at maturity.
As long as your pup is happy and healthy, I wouldn't worry too much about her size. You can mention it to your veterinarian at her next visit, so that he can reassure you as to her health, but otherwise just 'wait and see'.
Labrador Retrievers are large breed dogs, and as such are slow to mature. She has a lot of time to grow and develop, and it's important not to try to get her to grow more quickly or put on more weight than is normal for her. That can lead to all sorts of health issues.
She may end up catching uo with her sister in terms of size, or she may always be smaller, but it sounds as though she's healthy, has a great temperament and is very smart - next to all that her size is really not that important :o)
You may want to check out my Puppy Development and Puppy Weight Estimates pages so that you get an idea of the phases and stages she will go through, and maybe make an 'estimate' of how much she'll weigh when adult.
Hope this helps, best of luck with your pup.